Methods for treating attention-deficit/hyperactivity disorder

ABSTRACT

The invention is directed to a method of treating attention-deficit/hyperactivity disorder (ADHD) in a subject, comprising administering a therapeutically effective amount of a carbamoyl compound, or pharmaceutically acceptable salt thereof.

TECHNICAL FIELD

The present invention relates a method of treatingattention-deficit/hyperactivity disorder (ADHD). More specifically, thepresent invention is directed to a method of using a carbamate compoundalone or in combination with other medications, for the treatment ofADHD.

BACKGROUND ART

ADHD is a chronic developmental disorder characterized by issuesassociated with attention, inhibiting irrelevant stimuli, and/orfocusing too intensely on specific stimuli to the extent that thisinterferes with being productive at work or school. This disorder hasbeen found to be present in 3 to 10% of children and 1 to 6% of adultsand 50-66% of children continue to be affected by ADHD issues intoadulthood (Spencer et al., 2002; Daley, 2004). There is a high risk ofcigarette smoking and substance abuse in children with ADHD. Childrengrowing up with ADHD can face academic impairments, social dysfunctionand poor self-esteem.

The Diagnostic and Statistical Manual (DSM) IV defines five subtypes:predominately hyperactive/impulsive where patients shows 6 or morehyperactive/impulsive symptoms and fewer than 6 inattentive symptoms;predominately inattentive typo with 6 or more inattentive symptoms andfewer than 6 hyperactive/impulsivity symptoms; ADHD combined with 6 ormore hyperactive/impulsivity and inattentive symptoms; partial remissionwhere patient previous met criteria but currently only displays someimpairing symptoms; and ADHD not otherwise specified where full criteriaare not currently met and it is unclear that criteria were met in thepast (Murphy & Adler, 2004). Complications of diagnosis of especiallyadults include that there is no diagnostic test for ADHD, other comorbidconditions, clinical subjective judgment is needed to determineinterference of least 2 areas of life and the establishment of childhoodonset may not be possible. Conditions that can either mimic ADHDsymptoms or are comorbid with ADHD include conduct disorder,oppositional defiant disorder, major depressive disorder, anxietydisorder, bipolar disorder, learning disabilities and substance abuse(Spencer et al., 2002; Daley, 2004).

There is no clearly defined single etiology of ADHD. The pathophysiologyof ADHD may be impacted by genetics, prenatal and perinatal risk factorsand neurobiological deficits. Cigarette and alcohol exposure increasesthe risk along with a 75% genetic component (Spencer et al., 2002).Areas of the brain involved in attention including the prefrontal cortexwhere dopamine and norepinephrine receptors predominate have beendocumented to be smaller and less active in ADHD patients compared tocontrol implicating the catecholamines, dopamine and norpinephrine(Spencer et al., 2002; Orund et at, 2006; Rader et al., 2009).

The treatment of ADHD has been primarily with stimulant medicationincluding methylphenidate, dextroamphetamine and mixture of stimulantsas first-line treatment (Rader at al., 2009). Stimulant medications donot necessarily last for 24 hours even with extended releaseformulations. Thus, stimulants need to be taken 2 to 3 times dailyleading to compliance issues (Daughton & Kratochvil, 2009). However,compliance is improved with the extended release formulations byreducing stigma of taking medication at school but side effects continueuntil later in the day and tend to be expensive. Stimulants have thepotential for abuse and may not be ideal far comorbid conditionsincluding tic disorders (Spencer at al., 2002). In addition, there is aneed to monitor children for the impact of stimulant medication ongrowth (Daley, 2004) and for blood pressure and heart rate changes(Daughton & Kratochvil, 2009). Other side effects include appetitesuppression, weight loss, abdominal pain, headache, irritability,cardiovascular effects, insomnia, skin irritation and rash (Rader etal., 2009).

Nonstimulant treatments have also been effective with advantages oflonger duration of use, less abuse potential and treatment of comorbidconditions over stimulant medications (Daley, 2004). Atomoxetine,considered a second-line treatment, shows high selectivity for thepresynaptic norepinephrine transporter and promise in children andadults with ADHD with long lasting therapeutic effects and less abusepotential (Rader et al., 2009; Daughton & Kratochvil, 2009). However,the efficacy that atomoxetine achieved was not up to the level of thestimulants. In addition, efficacy onset is gradual and there is a riskof suicidal ideation, jaundice and potential interaction with CYP 2D6substrates.

Third-line treatments include tricyclic antidepressants, bupropion, andalpha₂ agonists (Rader et al., 2009). Tricyclic antidepressants withactions on catecholamine reuptake have been prescribed for ADHD but ICAaction is not selective and adverse effects include dry mouth, bloodpressure changes, weight gain, cardiac conduction delays andconstipation. Buproprion, antidepressant with dopamine and norpinephrineagonist effects, appears to be effective in ADHD but there is a higherrisk of drug-induced seizures albeit at higher dose levels, previoushistory of seizures and eating disorder (Daley, 2004). Side effects ofclonidine and guanfacine, alpha₂ agonists, are drowsiness, dizziness,dry mouth and orthostatic hypotension but these drugs are useful forpatients with conduct disorder and help counteract insomnia and appetitesuppression caused by stimulants (Ruder et al., 2009). Selectiveserotonin reuptake inhibitors have been investigated for ADHD butdemonstration of efficacy has not been promising (Spencer et al., 2002).

DISCLOSURE OF INVENTION Technical Problem

Accordingly, there is a need in the treatment of ADHD that would improveefficacy in the treatment of hyperactivity/impulsivity and inattentivesymptoms with greater compliance and lower adverse effect profileincluding abuse potential.

Solution to Problem

The present invention is directed to a method of treating ADHDcomprising the administration of a therapeutically effective amount of acompound having structural Formula (1) or a pharmaceutically acceptablesalt thereof, to a mammal in need of treatment:

wherein,

R is selected from the group consisting of hydrogen, lower alkyl of 1 to8 carbon atoms, halogen selected from F, Cl, Br and I, alkoxy of 1 to 3carbon atoms, nitro group, hydroxy, trifluoromethyl, and thioalkoxy of 1to 3 carbon atoms;

x is an integer of 1 to 3, with the proviso that R may be the same ordifferent when x is 2 or 3;

R₁ and R₂ can be the some or different from each other and areindependently selected from the group consisting of hydrogen, loweralkyl of 1 to 8 carbon atoms, aryl, arylalkyl, cycloalkyl of 3 to 7carbon atoms;

R₁ and R₂ can be joined to form a 5 to 7-membered heterocyclesubstituted with a member selected from the group consisting ofhydrogen, alkyl, and aryl group, wherein the heterocyclic compoundcomprises 1 to 2 nitrogen atoms and 0 to 1 oxygen atom, and the nitrogenatoms are not directly connected with each other or with the oxygenatom.

In another embodiment, the present invention provides a method ofimproving symptoms associated with ADHD in a subject, comprising thestep of the administration, to a subject in need of such treatment, of atherapeutically effective amount a compound of the Formula (1) or apharmaceutically acceptable salt thereof.

In further embodiment, the present invention provides a method ofameliorating or eliminating effects of ADHD in a subject, comprising thestep of the administration, to a subject in need of such treatment, of atherapeutically effective amount a compound of the Formula (1) or apharmaceutically acceptable salt thereof.

In additional embodiment, the present invention is directed topharmaceutical composition for treating ADHD comprising atherapeutically effective amount a compound of the formula (1) or apharmaceutically acceptable salt thereof.

In another embodiment, the present invention provides a pharmaceuticalcomposition for improving symptoms associated with ADHD in a subject,comprising a therapeutically effective amount a compound of the Formula(1) or a pharmaceutically acceptable salt thereof.

In further embodiment, the present invention provides a pharmaceuticalcomposition for ameliorating or eliminating symptoms of ADHD in asubject, comprising a therapeutically effective amount a compound of theFormula (1) or a pharmaceutically acceptable salt thereof.

The compound having structural Formula (1) is an enantiomersubstantially free of other enantiomers or an enantiomeric mixturewherein one enantiomer of the compound having structural Formula (1)predominates. One enantiomer predominates to the extent of about 90% orgreater, and preferably about 98% or greater.

The enantiomer is (S) or (L) enantiomer as represented by StructuralFormula (1a) or (R) or (D) enantiomer, as represented by StructuralFormula (1b):

Preferably, Rx, R₁ and R₂ are all selected from hydrogen and x is 1,which are shown in the following formula:

Embodiments of the invention include a method for using the enantiomerof Formula 1 substantially free of other enantiomers that is theenantiomer of Formula 1b or an enantiomeric mixture wherein theenantiomer of Formula 1b predominates. (Note: in the structural formulaof Formula 1b below the amino group attached to the beta carbon projectsinto the plane of the paper. This is the dextrorotary (D) enantiomerthat is of absolute configuration (R))

Advantageous Effects of Invention

The present invention is based in part on the discovery thatphenylalkylamino carbamates of Formula 1 discussed above have novel andunique pharmacological properties. These compounds have been shown inseveral animal models to have the ability to treat ADHD and modificationof symptoms associated with ADHD.

Although the precise mechanism of action is not completely understood,it is known that these compounds do not work by the same mechanisms asmost other known treatments for ADHD. For these reasons, the compoundsof Formula 1 are especially suitable for use as sole or adjunctivetreatment for ADHD and modification of symptoms associated with ADHD.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1: Effect of Test Compound on Percent Accuracy During Phase IIReversal Training of a Visual Discrimination.

FIG. 2: Effect of Test Compound on the Number of Sessions Required toReach Criteria in Phase II Reversal Training of a Visual Discrimination.

FIG. 3: Effect of Test Compound and Amphetamine on locomotor activity.

FIG. 4: Effects of administration of Test Compound or vehicle onextracellular dopamine concentrations in the striatum of rats.

FIG. 5: Effects of administration of Test Compound or vehicle onextracellular norepinephrine concentrations in the prefrontal cortex ofrats.

BEST MODE FOR CARRYING OUT THE INVENTION

These and other objects of the invention will be mom fully understoodfrom the following description of the invention, the referenced drawingsattached hereto and the claims appended hereto.

The present invention is directed to a method of treating ADHDcomprising the administration of a therapeutically effective amount of acompound having structural Formula (1) or enantiomers, diastereomers,racemates or mixtures thereof, or hydrates, solvates andpharmaceutically acceptable salts and amides thereof, to a mammal inneed of treatment:

wherein,

R is selected from the group consisting of hydrogen, lower alkyl of 1 to8 carbon atoms, halogen selected from F, Cl, Br and I, alkoxy of 1 to 3carbon atoms, nitro group, hydroxy, trifluoromethyl, and thioalkoxy of 1to 3 carbon atoms;

x is an integer of 1 to 3, with the proviso that R may be the same ordifferent when x is 2 or 3;

R₁ and R₂ can be the same or different from each other and areindependently selected from the group consisting of hydrogen, loweralkyl of 1 to 8 carbon atoms, aryl, arylalkyl, cycloalkyl of 3 to 7carbon atoms;

R₁ and R₂ can be joined to form a 5 to 7-membered heterocyclesubstituted with a member selected from the group consisting ofhydrogen, alkyl, and aryl groups, wherein the heterocyclic compoundcomprises 1 to 2 nitrogen atoms and 0 to 1 oxygen atom, and the nitrogenatoms are not directly connected with each other or with the oxygenatom.

The present method also includes the use of a compound selected from thegroup consisting Formula 1a or 1b, or enantiomers, diastereomers,racemates or mixtures thereof, or hydrates, solvates andpharmaceutically acceptable salts and amides thereof:

wherein Rx, R₁ and R₂ are the same as defined above.

The present method also preferably includes the use of the D (ordextrorotary) enantiomer (of absolute configuration R) selected from thegroup consisting of Formula 1 or an enantiomeric mixture thereof. In thestructural formula of Formula 1b, the amino group attached to the betacarbon projects into the plane of the paper. This is the dextrorotary(D) enantiomer that is of absolute configuration (R).

Preferably, in the Structural Formula 1, Rx, R₁ and R₂ are hydrogen andx is 1 as represented by following Structural Formula:

O-carbamoyl-(D)-phenylalaninol is also named(R)-(beta-amino-benzenepropyl) carbamate monohydrochloric acid. Forenantiomeric mixtures, wherein O-carbamoyl-(D)-phenylalaninolpredominates, preferably, to the extent of about 90% or greater, andmore preferably about 98% or greater.

The compounds of Formula 1 can be synthesized by methods known to askilled person in the art. Some reaction schemes for synthesizingcompounds of Formula (1) have been described in published; U.S. Pat. No.5,705,640, U.S. Pat. No. 5,756,817, U.S. Pat. No. 5,955,499, and U.S.Pat. No. 6,140,532. Details of the above reactions schemes as well asrepresentative examples on the preparation of specific compounds havebeen described in published; U.S. Pat. No. 5,705,640. U.S. Pat. No.5,756,817, U.S. Pat. No. 5,955,499, U.S. Pat. No. 6,140,532, allincorporated herein by reference in their entirety.

The salts of the compounds of Formula (i) can be produced by treatingthe compound with an acid (HX) in suitable solvent or by means wellknown to those of skill in the art.

From Structural Formula 1, it is evident that some of the compounds ofthe invention have at least one and possibly more asymmetric carbonatoms. It is intended that the present invention include within itsscope the stereochemically pure isomeric forms of the compounds as wellas their racemates. Stereochemically pure isomeric forms may be obtainedby the application of art known principles. Diastereoisomers may beseparated by physical separation methods such as fractionalcrystallization and chromatographic techniques, and enantiomers may beseparated from each other by the selective crystallization of thediasteromeric salts with optically active acids or bases or by chiralchromatography. Pure stereoisomers may also be prepared syntheticallyfrom appropriate stereochemically pure starting materials, or by usingstereoselective reactions.

During any of the processes for preparation of the compounds of thepresent invention, it may be necessary and/or desirable to protectsensitive or reactive groups on any of the molecules concerned. This maybe achieved by means of conventional protecting groups, such as thosedescribed in Protective Groups in Organic Chemistry, ed. J. F. W.McOmie, Plenum Press, 1973; and T. W. Greene & P. G. M. Wuts, ProtectiveGroups in Organic Synthesis, Third Edition, John Wiley & Sons, 1999. Theprotecting groups may be removed at a convenient subsequent stage usingmethods known from the art.

The present invention is based in part on the discovery thatphenylalkylamino carbamates of Formula 1 discussed above have novel andunique pharmacological properties. These compounds have been shown inseveral animal models to have the ability to treat ADHD and modificationof symptoms associated with ADHD.

Although the precise mechanism of action is not completely understood,it is known that these compounds do not work by the same mechanisms asmost other known treatments for ADHD. For these reasons, the compoundsof Formula 1 are especially suitable for use as sole or adjunctivetreatment for ADHD and modification of symptoms associated with ADHD.

Thus, these compounds can be safely used alone or in combination withother useful medications to provide enhanced efficacy and reduced sideeffects because smaller doses of each drug that could be used.

In one aspect, this invention relates to methods to treat subjectssuffering from ADHD; the method comprising delivering to the subject atherapeutically effective amount of one or more of the carbamatecompounds of the invention or a pharmaceutically acceptable salt thereofand a pharmaceutically acceptable carrier, diluent or excipient.

In another aspect, this invention also provides a method fordiminishing, inhibiting or eliminating the symptoms of ADHD includinghyperactivity/impulsivity and inattentive symptoms in a subjectsuffering from ADHD which comprises administering to the subject aneffective amount of carbamate compounds of the invention to diminish,inhibit or eliminate said symptoms.

Definitions

For convenience, certain terms employed in the specification, examples,and appended claims are collected here.

It is to be understood that this invention is not limited to theparticular methodology, protocols, animal species or genera, andreagents described, as such may vary. It is also to be understood thatthe terminology used herein is for the purpose of describing particularembodiments only, and is not intended to limit the scope of the presentinvention that will be limited only by the appended claims,

As used herein the term “subject” refers to an animal, preferably amammal, and most preferably a human both male and female, who has beenthe object of treatment, observation or experiment.

The term “therapeutically effective amount” as used herein, means thatamount of active compound or pharmaceutical agent that elicits thebiological or medicinal response in a tissue system, animal or humanthat is being sought by a researcher, veterinarian, medical doctor orother clinician, which includes alleviation of one or more of the signsor symptoms of the disease or disorder being treated.

The term “prophylactically effective amount” is intended to mean thatamount of a pharmaceutical drug that will prevent or reduce the risk ofoccurrence of the biological or medical event that is sought to beprevented of a tissue, a system, animal or human that is being sought bya researcher, veterinarian, medical doctor or other clinician.

The term “pharmaceutically acceptable salts” shall mean non-toxic saltsof the compounds employed in this invention which are generally preparedby reacting the free acid with a suitable organic or inorganic base.Examples of such salts include, but are not limited to, acetate,benzenesulfonate, benzoate, bicarbonate, bisulfate, bitartrate, borate,bromide, calcium, calcium edetate, camsylate, carbonate, chloride,clavulanate, citrate, dihydrochloride, edetate, edisylate, estolate,esylate, fumarate, gluceptate, gluconate, glutamate,glycollylarsanilate, hexylresorcinate, hydrabamine, hydrobromide,hydrochloride, hydroxynaphthoate, iodide, isothionate, lactate,lactobionate, laurate, malate, maleate, mandelate, mesylate,methylbromide, methylnitrate, methylsulfate, mucate, napsylate, nitrate,oleate, oxalate, pamaote, palmitate, panthothenate,phosphate/diphosphate, polygalacturonate, potassium, salicylate, sodium,stearate, subacetate, succinate, tannate, tartrate, teoclate, tosylate,triethiodide, valerate.

Therefore, the term “a patient in need of treatment” as used herein willrefer to any subject or patient who currently has or may develop any ofthe above syndromes or disorders, including any mood disorder which canbe treated by antidepressant medication, or any other disorder in whichthe patient s present clinical condition or prognosis could benefit fromthe administration of one or more compounds of Formula (1) alone or incombination with another therapeutic intervention including but notlimited to another medication.

The term “treating” or “treatment” as used herein, refers to any indiciaof success in the prevention or amelioration of an injury, pathology orcondition of ADHD and modification of symptoms of ADHD, including anyobjective or subjective parameter such as abatement: remission;diminishing of symptoms or making the injury, pathology, or conditionmore tolerable to the patient; slowing in the rate of degeneration ordecline or worsening of the illness: making the final point of worseningless debilitating: or improving a subject's physical or mentalwell-being. The treatment or amelioration of symptoms can be based onobjective or subjective parameters; including the results of a physicalexamination, neurological examination, and/or psychiatric evaluations.Accordingly, the term “treating” or “treatment” includes theadministration of the compounds or agents of the present invention fortreatment of any form of ADHD in both males and females. In someinstances, treatment with the compounds of the present invention willdone in combination with other compounds to prevent, inhibit, or arrestthe progression of the ADHD.

The term “therapeutic effect” as used herein, refers to the effectiveimprovement in or reduction of symptoms of ADHD. The term “atherapeutically effective amount” as used herein means a sufficientamount of one or more of the compounds of the invention to produce atherapeutic effect, as defined above, in a subject or patient in need ofsuch ADHD treatment.

The terms “subject” or “patient” are used herein interchangeably and asused herein mean any mammal including but not limited to human beingsincluding a human patient or subject to which the compositions of theinvention can be administered. The term mammals include human patients,both male and female and non-human primates, as well as experimentalanimals such as rabbits, rats, and mice, and other animals.

Methods are known in the art for determining therapeutically andprophylactically effective doses for the instant pharmaceuticalcomposition. For example the compound can be employed at a daily dose inthe range of about 0.1 mg to 400 mg usually on a regimen of 1 to 2 timesper day, for an average adult human. The effective amount, however, maybe varied depending upon the particular compound used, the mode ofadministration, the strength of the preparation, the mode ofadministration, and the advancement of the disease condition. Inaddition, factors associated with the particular patient being treated,including patient age, weight, diet and time of administration, willresult in the need to adjust dosages.

The compound may be administered to a subject by any conventional routeof administration, including, but not limited to, intravenous, oral,subcutaneous, intramuscular, intradermal and parenteral. Depending onthe route of administration, compounds of Formula (1) can be constitutedinto any form. For example, forms suitable for oral administrationinclude solid forms, such as pills, gelcaps, tablets, caplets, capsules(each including immediate release, timed release and sustained releaseformulations), granules, and powders. Forms suitable for oraladministration also include liquid forms, such as solutions, syrups,elixirs, emulsions, and suspensions. In addition, forms useful forparenteral administration include sterile solutions, emulsions andsuspensions.

To prepare the pharmaceutical compositions of this invention, one ormore compounds of formula (1) or salt thereof as the active ingredientIs intimately admixed with a pharmaceutical carrier according toconventional pharmaceutical compounding techniques. Carriers arenecessary and inert pharmaceutical excipients, including, but notlimited to, binders, suspending agents, lubricants, flavorings,sweeteners, preservatives, dyes, and coatings. In preparing compositionsin oral dosage form, any of the usual pharmaceutical carries may beemployed. For example, for liquid oral preparations, suitable carriersand additives include water, glycols, oils, alcohols, flavoring agents,preservatives, coloring agents and the like; for solid oralpreparations, suitable carriers and additives include starches, sugars,diluents, granulating agents, lubricants, binders, disintegrating agentsand the like. For parenteral use, the carrier will usually comprisesterile water, though other ingredients, for example, for purposes suchas aiding solubility or for preservation, may be included. Injectablesuspensions may also be prepared, in which case appropriate liquidcarriers, suspending agents and the like may be employed,

Because of their ease in administration, tablets and capsules representthe most advantageous oral dosage unit form, in which case solidpharmaceutical carriers are obviously employed. If desired, tablets maybe sugar coated or enteric coated by standard techniques. Suppositoriesmay be prepared, in which case cocoa butter could be used as thecarrier. The tablets or pills can be coated or otherwise compounded toprovide a dosage form affording the advantage of prolonged action. Forexample, the tablet or pills can comprise an inner dosage and an outerdosage component, the latter being in the form of an envelope over theformer. The two components can be separated by an enteric layer, whichserves to resist disintegration in the stomach and permits the innercomponent to pass intact into the duodenum or to be delayed in release.A variety of material can be used for such enteric layers or coatings,such materials including a number of polymeric acids with such materialsas shellac, cetyl alcohol and cellulose acetate.

The active drug can also be administered in the form of liposomedelivery systems, such as small unilamellar vesicles, large unilamellarvesicles and multilamellar vesicles. Liposomes can be formed from avariety of phospholipids, such as cholesterol, stearylamine orphosphatidylcholines.

Active drug may also be delivered by the use of monoclonal antibodies asindividual carriers to which the compound molecules are coupled. Activedrug may also be coupled with soluble polymers as targetable drugcarriers. Such polymers can include polyvinyl-pyrrolidone, pyrancopolymer, polyhydroxypropyl-methacrylamide-phenol,polyhydroxy-ethyl-aspartamide-phenol, or polyethyleneoxide-polylysinesubstituted with palmitoyl residues. Furthermore, active drug may becoupled to a class of biodegradable polymers useful in achievingcontrolled release of a drug, for example, polylactic acid, polyglycolicacid, copolymers of polylactic and polyglycolic acid, polyepsiloncaprolactone, polyhydroxy butyric acid, polyorthoesters, polyacetals,polydihydropyrans, polycyanoacrylates and cross linked or amphipathicblock copolymers of hydrogels.

Preferably these compositions are in unit dosage forms such as tablets,pills, capsules, powders, granules, sterile parenteral solutions orsuspensions, metered aerosol or liquid sprays, drops, ampoules,auto-injector devices or suppositories, for oral parenteral, intranasal,sublingual or rectal administration, or for administration by inhalationor insufflation.

Alternatively, the composition may be presented in a form suitable foronce-weekly or once-monthly administration; for example, an insolublesalt of the active compound, such as the decanoate salt, may be adaptedto provide a depot preparation for intramuscular injection.

The pharmaceutical compositions herein will contain, per dosage unit,e.g., tablet, capsule, powder, injection, teaspoonful, suppository andthe like, an amount of the active ingredient necessary to deliver aneffective dose as described above. For example, the pharmaceuticalcompositions herein can contain, per unit dosage unit, from about 25 toabout 400 mg of the active ingredient. Preferably, the range is fromabout 50 to about 200 mg of the active ingredient.

In some embodiments of the present invention carbamate compoundssuitable for use in the practice of this invention will be administeredeither singly or concomitantly with at least one or more other compoundsor therapeutic agents. In these embodiments, the present inventionprovides methods to treat ADHD and modification of symptoms associatedwith ADHD in a patient. The method includes the step of; administeringto a patient in need of treatment, an effective amount of one of thecarbamate compounds disclosed herein in combination with an effectiveamount of one or more other compounds or therapeutic agents.

It is understood that substituents and substitution patterns on thecompounds of the present invention can be selected by one of ordinaryskill in the art to provide compounds that are chemically stable andthat can be readily synthesized by techniques known in the art as wellas the methods provided herein.

The present invention includes the use of isolated enantiomers ofFormula 1. In one preferred embodiment, a pharmaceutical compositioncomprising the isolated S-enantiomer of Formula 1 is used to provideADHD treatment in a subject. In another preferred embodiment, apharmaceutical composition comprising the isolated R-enantiomer ofFormula 1 is used to provide ADHD treatment a subject

The present invention also includes the use of mixtures of enantiomersof Formula 1. In one aspect of the present invention, one enantiomerwill predominate. An enantiomer that predominates in the mixture Is onethat is present in the mixture in an amount greater than any of theother enantiomers present in the mixture, e.g., in an amount greaterthan 50%. In one aspect, one enantiomer will predominate to the extentof 90% or to the extent of 91%, 92%, 93%, 94%, 95%, 96%, 97% or 98% orgreater. In one preferred embodiment, the enantiomer that predominatesin a composition comprising a compound of Formula 1 is the S-enantiomerof Formula 1.

The present invention provides methods of using enantiomers andenantiomeric mixtures of compounds represented by Formula 1. A carbamateenantiomer of Formula 1 contains a chiral center on the second aliphaticcarbon adjacent to the phenyl ring.

An enantiomer that is Isolated is one that is substantially free of thecorresponding enantiomer. Thus, an isolated enantiomer refers to acompound that is separated via separation techniques or prepared free ofthe corresponding enantiomer. The term “substantially free”, as usedherein, means that the compound is made up of a significantly greaterproportion of one enantiomer. In preferred embodiments, the compoundincludes at least about 90% by weight of a preferred enantiomer. Inother embodiments of the invention, the compound Includes at least about99% by weight of a preferred enantiomer. Preferred enantiomers can beisolated from racemic mixtures by any method known to those skilled inthe art, including high performance liquid chromatography (HPLC) and theformation and crystallization of chiral salts, or preferred enantiomerscan be prepared by methods described herein.

Carbamate Compounds as Pharmaceuticals:

The present invention provides racemic mixtures, enantiomeric mixturesand isolated enantiomers of Formula 1 as pharmaceuticals. The carbamatecompounds are formulated as pharmaceuticals to provide anti-ADHD actionin a subject.

In general, the carbamate compounds of the present invention can beadministered as pharmaceutical compositions by any method known in theart for administering therapeutic drugs including oral, buccal, topical,systemic (e.g., transdermal, Intranasal, or by suppository), orparenteral (e.g., intramuscular, subcutaneous, or intravenousinjection.) Administration of the compounds directly to the nervoussystem can include, for example, administration to intracerebral,intraventricular, intracerebroventricular, intrathecal, intracisternal,intraspinal or peri-spinal routes of administration by delivery viaintracranial or intravertebral needles or catheters with or without pumpdevices.

Compositions can take the form of tablets, pills, capsules, semisolids,powders, sustained release formulations, solutions, suspensions,emulsions, syrups, elixirs, aerosols, or any other appropriatecompositions; and comprise at least one compound of this invention incombination with at least one pharmaceutically acceptable excipient.Suitable excipients are well known to persons of ordinary skill in theart, and they, and the methods of formulating the compositions, can befound in such standard references as Alfonso A R: Remington'sPharmaceutical Sciences, 17th ed., Mack Publishing Company, Easton Pa.,1985, the disclosure of which is incorporated herein by reference in itsentirety and for all purposes. Suitable liquid carriers, especially forinjectable solutions, include water, aqueous saline solution, aqueousdextrose solution, and glycols.

The carbamate compounds can be provided as aqueous suspensions. Aqueoussuspensions of the invention can contain a carbamate compound inadmixture with excipients suitable for the manufacture of aqueoussuspensions. Such excipients can include, for example, a suspendingagent, such as sodium carboxymethylcellulose, methylcellulose,hydroxypropylmethylcellulose, sodium alginate, polyvinylpyrrolidone, gumtragacanth and gum acacia, and dispersing or wetting agents such as anaturally occurring phosphatide (e.g., lecithin), a condensation productof an alkylene oxide with a fatty acid (e.g., polyoxyethylene stearate),a condensation product of ethylene oxide with a long chain aliphaticalcohol (e.g., heptadecathylene oxycetanol), a condensation product ofethylene oxide with a partial ester derived from a fatty acid and ahexitol (e.g., polyoxyethylene sorbitol mono-oleate), or a condensationproduct of ethylene oxide with a partial ester derived from fatty acidand a hexitol anhydride (e.g., polyoxyethylene sorbitan mono-oleate).

The aqueous suspension can also contain one or more preservatives suchas ethyl or n-propyl p-hydroxybenzoate, one or more coloring agents, oneor more flavoring agents, and one or more sweetening agents, such assucrose, aspartame or saccharin. Formulations can be adjusted forosmolarity.

Oil suspensions for use in the present methods can be formulated bysuspending a carbamate compound in a vegetable oil, such as arachis oil,olive oil, sesame oil or coconut oil, or in a mineral oil such as liquidparaffin; or a mixture of these. The oil suspensions can contain athickening agent, such as beeswax, hard paraffin or cetyl alcohol.Sweetening agents can be added to provide a palatable oral preparation,such as glycerol, sorbitol or sucrose. These formulations can bepreserved by the addition of an antioxidant such as ascorbic acid. As anexample of an injectable oil vehicle, see Minto, J, Pharmacol. Exp.Ther. 281:93-102, 1997. The pharmaceutical formulations of the inventioncan also be in the form of oil-in-water emulsions. The oily phase can bea vegetable oil or a mineral oil, described above, or a mixture ofthese.

Suitable emulsifying agents include naturally occurring gums, such asgum acacia and gum tragacanth, naturally occurring phosphatides, such assoybean lecithin, esters or partial esters derived from fatty acids andhexitol anhydrides, such as sorbitan mono-oleate, and condensationproducts of these partial esters with ethylene oxide, such aspolyoxyethylene sorbitan mono-oleate. The emulsion can also containsweetening agents and flavoring agents, as in the formulation of syrupsand elixirs. Such formulations can also contain a demulcent, apreservative, or a coloring agent.

The compound of choice, alone or in combination with other suitablecomponents can be made into aerosol formulations (i.e., they can be“nebulized”) to be administered via inhalation. Aerosol formulations canbe placed into pressurized acceptable propellants, such asdichlorodifluoromethane, propane, nitrogen, and the like.

Formulations of the present invention suitable for parenteraladministration, such as, for example, by intraarticular (in the joints),intravenous, intramuscular, intradermal, intraperitoneal, andsubcutaneous routes, can include aqueous and non-aqueous, isotonicsterile injection solutions, which can contain antioxidants, buffers,bacteriostats, and solutes that render the formulation isotonic with theblood of the intended recipient, and aqueous and non-aqueous sterilesuspensions that can include suspending agents, solubilizers, thickeningagents, stabilizers, and preservatives. Among the acceptable vehiclesand solvents that can be employed are water and Ringer's solution, anisotonic sodium chloride. In addition, sterile fixed oils canconventionally be employed as a solvent or suspending medium. For thispurpose, any bland fixed oil can be employed including synthetic mono-or diglycerides. In addition, fatty acids such as oleic acid canlikewise be used in the preparation of injectables. These solutions aresterile and generally free of undesirable matter.

Where the compounds are sufficiently soluble they can be dissolveddirectly in normal saline with or without the use of suitable organicsolvents, such as propylene glycol or polyethylene glycol. Dispersionsof the finely divided compounds can be made-up in aqueous starch orsodium carboxymethyl cellulose solution, or in suitable oil, such asarachis oil. These formulations can be sterilized by conventional,well-known sterilization techniques. The formulations can containpharmaceutically acceptable auxiliary substances as required toapproximate physiological conditions such as pH adjusting and bufferingagents, toxicity adjusting agents, e.g., sodium acetate, sodiumchloride, potassium chloride, calcium chloride, sodium lactate and thelike.

The concentration of a carbamate compound in these formulations can varywidely, and will be selected primarily based on fluid volumes,viscosities, body weight, and the like, in accordance with theparticular mode of administration selected and the patient's needs. ForIV administration, the formulation can be a sterile injectablepreparation, such as a sterile injectable aqueous or oleaginoussuspension. This suspension can be formulated according to the known artusing those suitable dispersing or wetting agents and suspending agents.The sterile injectable preparation can also be a sterile injectablesolution or suspension in a nontoxic parenterally acceptable diluents orsolvent, such as a solution of 1,3-butanediol. The formulations ofcommends can be presented in unit-dose or multi-dose sealed containers,such as ampoules and vials. Injection solutions and suspensions can beprepared from sterile powders, granules, and tablets of the kindpreviously described.

A carbamate compound suitable for use in the practice of this inventioncan be and is preferably administered orally. The amount of a compoundof the present invention in the composition can vary widely depending onthe type of composition, size of a unit dosage, kind of excipients, andother factors well known to those of ordinary skill in the art. Ingeneral, the final composition can comprise, for example, from 0.000001percent by weight (% w) to 50% w of the carbamate compound, preferably0.00001% w to 25% w, with the remainder being the excipient orexcipients.

Pharmaceutical formulations for oral administration can be formulatedusing pharmaceutically acceptable carriers well known in the art indosages suitable for oral administration. Such carriers enable thepharmaceutical formulations to be formulated in unit dosage forms astablets, pills, powder, dragees, capsules, liquids, lozenges, gels,syrups, slurries, suspensions, etc. suitable for ingestion by thepatient.

Formulations suitable for oral administration can consist of (a) liquidsolution, such as an effective amount of the pharmaceutical formulationsuspended in a diluents, such as water, saline or polyethyleneglycol(PEG) 400; (b) capsules, sachets or tablets, each containing apredetermined amount of the active ingredient, as liquids, solids,granules or gelatin; (c) suspensions in an appropriate liquid; and (d)suitable emulsions.

Pharmaceutical preparations for oral use can be obtained throughcombination of the compounds of the present invention with a solidexcipient, optionally grinding a resulting mixture, and processing themixture of granules, after adding suitable additional compounds, ifdesired, to obtain tablets or dragee cores. Suitable solid excipientsare carbohydrate or protein fillers and include, but are not limited tosugars, including lactose, sucrose, mannitol, or sorbitol; starch fromcorn, wheat, rice, potato, or other plants; cellulose such as methylcellulose, hydroxymethyl cellulose, hydroxypropylmethyl-cellulose orsodium carboxymethylcellulose; and gums including arabic and tragacanth;as well as proteins such as gelatin and collagen.

If desired, disintegrating or solubilizing agents can be added, such asthe cross-linked polyvinyl pyrrolidone, agar, alginic acid, or a saltthereof, such as sodium alginate. Tablet forms can include one or moreof lactose, sucrose, mannitol, sorbitol, calcium phosphates, cornstarch, potato starch, microcrystalline cellulose, gelatin, colloidalsilicon dioxide, talc, magnesium stearate, stearic acid, and otherexcipients, colorants, fillers, binders, diluents, buffering agents,moistening agents, preservatives, flavoring agents, dyes, disintegratingagents, and pharmaceutically compatible carriers. Lozenge forms cancomprise the active ingredient in a flavor, e.g., sucrose, as well aspastilles comprising the active ingredient in an inert base, such asgelatin and glycerin or sucrose and acacia emulsions, gels, and the likecontaining, in addition to the active ingredient, carriers known in theart.

The compounds of the present Invention can also be administered in theform of suppositories for rectal administration of the drug. Theseformulations can be prepared by mixing the drug with a suitablenon-irritating excipient that is solid at ordinary temperatures butliquid at the rectal temperatures and will therefore melt in the rectumto release the drug. Such materials are cocoa butter and polyethyleneglycols.

The compounds of the present invention can also be administered byintranasal, intraocular, intravaginal, and intrarectal routes includingsuppositories, insufflation, powders and aerosol formulations (forexamples of steroid inhalants, see Rohatagi, J. Clin. Pharmacol.35:1187-1193, 1995; Tjwa, Ann. Allergy Asthma Immunol. 75:107-111,1995).

The compounds of the present invention can be delivered transdermally,by a topical route, formulated as applicator sticks, solutions,suspensions, emulsions, gels, creams, ointments, pastes, jellies,paints, powders, and aerosols.

Encapsulating materials can also be employed with the compounds of thepresent invention and the term “composition” can include the activeingredient in combination with an encapsulating material as aformulation, with or without other carriers. For example, the compoundsof the present invention can also be delivered as microspheres for slowrelease in the body. In one embodiment, microspheres can be administeredvia intradermal injection of drug (e.g., mifepristone)-containingmicrospheres, which slowly release subcutaneously (see Rao, J. BiomaterSci. Polym. Ed. 7:623-645, 1995; as biodegradable and injectable gelformulations (see, e.g., Gao, Pharm. Res. 12:857-863, 1995); or, asmicrospheres for oral administration (see, e.g., Eyles, J. Pharm.Pharmacol. 49:669-674, 1997). Both transdermal and intradermal routesafford constant delivery for weeks or months. Cachets can also be usedin the delivery of the compounds of the present invention.

In another embodiment, the compounds of the present invention can bedelivered by the use of liposomes which fuse with the cellular membraneor are endocytosed, i.e., by employing ligands attached to the liposomethat bind to surface membrane protein receptors of the cell resulting inendocytosis. By using liposomes, particularly where the liposome surfacecarries ligands specific for target cells, or are otherwisepreferentially directed to a specific organ, one can focus the deliveryof the carbamate compound into target cells in vivo. (See, e.g.,Al-Muhammed, I. Microencapsul. 13:293-306, 1996; Chonn, Curr. Opin.Biotechnol. 6:698-708, 1995; Ostro, Am, J. Hosp. Pharm. 46:1576-1587,1989).

The pharmaceutical formulations of the invention can be provided as asalt and can be formed with many acids, including but not limited tohydrochloric, sulfuric, acetic, lactic, tartaric, malic, succinic, etc.Salts tend to be more soluble in aqueous or other protonic solvents thatare the corresponding free base forms. In other cases, the preferredpreparation can be a lyophilized powder which can contain, for example,any or all of the following: 1 mM-50 mM histidine, 0.1%-2% sucrose,2%-7% mannitol, at a pH range of 4.5 to 5.5, that is combined withbuffer prior to use.

Pharmaceutically acceptable salts refer to salts that arepharmaceutically acceptable and have the desired pharmacologicalproperties. Such salts include salts that may be formed where acidicprotons present in the compounds are capable of reacting with inorganicor organic bases. Suitable inorganic salts include those formed with thealkali metals, e.g. sodium and potassium, magnesium, calcium, andaluminum. Suitable organic salts include those formed with organic basessuch as the amine bases, e.g. ethanolamine, diethanolamine,triethanolamine, tromethamine, N methylglucamine, and the like.Pharmaceutically acceptable salts can also include acid addition saltsformed from the reaction of amine moieties in the parent compound withinorganic acids (e.g. hydrochloric and hydrobromic acids) and organicacids (e.g. acetic acid, citric acid, maleic acid, and the alkane- andarene-sulfonic acids such as methanesulfonic acid and benzenesulfonicacid). When there are two acidic groups present, a pharmaceuticallyacceptable salt may be a mono-acid-mono-salt or a di-salt; and similarlywhere there are more than two acidic groups present, some or all of suchgroups can be salified.

Compounds named in this invention can be present in unsalified form, orin salified form, and the naming of such compounds is intended toinclude both the original (unsalified) compound and its pharmaceuticallyacceptable salts. The present invention includes pharmaceuticallyacceptable salt forms of Formula (I). More than one crystal form of anenantiomer of Formula 1 can exist and as such are also included in thepresent invention.

A pharmaceutical composition of the invention can optionally contain, inaddition to a carbamate compound, at least one other therapeutic agentuseful in the treatment of ADHD. For example, the carbamate compounds ofFormula 1 can be combined physically with other ADHD treatments in fixeddose combinations to simplify their administration.

Methods of formulating pharmaceutical compositions have been describedin numerous publications such as Pharmaceutical Dosage Forms: Tablets.Second Edition, Revised and Expanded, Volumes 1-3, edited by Liebermanet al: Pharmaceutical Dosage Forms: Parenteral Medications. Volumes 1-2,edited by Avis et al; and Pharmaceutical Dosage Forms: Disperse Systems.Volumes 1-2, edited by Lieberman et al; published by Marcel Dekker, Inc,the disclosure of which are herein incorporated by reference in theirentireties and for all purposes.

The pharmaceutical compositions are generally formulated as sterile,substantially isotonic and in full compliance with all GoodManufacturing Practice (GMP) regulations of the U.S. Food and DrugAdministration.

Dosage Regimens

The present invention provides methods of providing anti-ADHD action ina mammal using carbamate compounds. The amount of the carbamate compoundnecessary to reduce or treat ADHD is defined as a therapeutically or apharmaceutically effective dose. The dosage schedule and amountseffective for this use, i.e., the dosing or dosage regimen will dependon a variety of factors including the stage of the disease, thepatient's physical status, age and the like. In calculating the dosageregimen for a patient, the mode of administration is also taken intoaccount.

A person of ordinary skill in the art will be able without undueexperimentation, having regard to that skill and this disclosure, todetermine a therapeutically effective amount of a particular substitutedcarbamate compound for practice of this invention (see, e.g., Lieberman,Pharmaceutical Dosage Forms (Vols. 1-3, 1992); Lloyd, 1999, The art,Science and Technology of Pharmaceutical Compounding; and Pickar, 1999,Dosage Calculations). A therapeutically effective dose is also one inwhich any toxic or detrimental side effects of the active agent that isoutweighed in clinical terms by therapeutically beneficial effects. Itis to be further noted that for each particular subject, specific dosageregimens should be evaluated and adjusted over time according to theindividual need and professional judgment of the person administering orsupervising the administration of the compounds.

For treatment purposes, the compositions or compounds disclosed hereincan be administered to the subject in a single bolus delivery, viacontinuous delivery over an extended time period, or in a repeatedadministration protocol (e.g., by an hourly, daily or weekly, repeatedadministration protocol). The pharmaceutical formulations of the presentinvention can be administered, for example, one or more times daily, 3times per week, or weekly. In one embodiment of the present invention,the pharmaceutical formulations of the present invention are orallyadministered once or twice daily.

In this context, a therapeutically effective dosage of the carbamatecompounds can include repeated doses within a prolonged treatmentregimen that will yield clinically significant results to treat ADHD.Determination of effective dosages in this context is typically based onanimal model studies followed up by human clinical trials and is guidedby determining effective dosages and administration protocols thatsignificantly reduce the occurrence or severity of targeted exposuresymptoms or conditions in the subject. Suitable models in this regardinclude, for example, murine, rat, porcine, feline, non-human primate,and other accepted animal model subjects known in the art.Alternatively, effective dosages can be determined using in vitro models(e.g., immunologic and histopathologic assays). Using such models, onlyordinary calculations and adjustments are typically required todetermine an appropriate concentration and dose to administer atherapeutically effective amount of the biologically active agent(s)(e.g., amounts that are intranasally effective, transdermally effective,intravenously effective, or intramuscularly effective to elicit adesired response).

In an exemplary embodiment of the present invention, unit dosage formsof the compounds are prepared for standard administration regimens. Inthis way, the composition can be subdivided readily into smaller dosesat the physician's direction. For example, unit dosages can be made upin packeted powders, vials or ampoules and preferably in capsule ortablet form.

The active compound present in these unit dosage forms of thecomposition can be present in an amount of, for example, from about 10mg to about one gram or more, for single or multiple dailyadministration, according to the particular need of the patient. Byinitiating the treatment regimen with a minimal daily dose of about onegram, the blood levels of the carbamate compounds can be used todetermine whether a larger or smaller dose is indicated.

Effective administration of the carbamate compounds of this inventioncan be administered, for example, at an oral or parenteral dose of fromabout 0.01 mg/kg/dose to about 150 mg/kg/dose. Preferably,administration will be from about 0.1 mg/kg/dose to about 25 mg/kg/dose,more preferably from about 0.2 to about 18 mg/kg/dose. Therefore, thetherapeutically effective amount of the active ingredient contained perdosage unit as described herein can be, for example, from about 1 mg/dayto about 7000 mg/day for a subject having, for example, an averageweight of 70 kg.

The methods of this invention also provide for kits for use in providingtreatment of ADHD. After a pharmaceutical composition comprising one ormore carbamate compounds of this invention, with the possible additionof one or more other compounds of therapeutic benefit, has beenformulated in a suitable carrier, it can be placed in an appropriatecontainer and labeled for providing ADHD treatment. Additionally,another pharmaceutical comprising at least one other therapeutic agentuseful in the ADHD treatment can be placed in the container as well andlabeled for treatment of the indicated disease. Such labeling caninclude, for example, instructions concerning the amount, frequency andmethod of administration of each pharmaceutical.

Although the foregoing invention has been described in detail by way ofexample for purposes of clarity of understanding, it will be apparent tothe artisan that certain changes and modifications are comprehended bythe disclosure and may be practiced without undue experimentation withinthe scope of the appended claims, which are presented by way ofillustration not limitation. The following examples are provided toillustrate specific aspects of the invention and are not meant to belimitations.

A better understanding of the present invention may be obtained in Lightof the following examples that are set forth to illustrate, but are notto be construed to limit, the present invention.

MODE FOR THE INVENTION Example 1

The test compound (O-carbamoyl-(D)-phenylalaninol) administered at 3, 10or 30 mg/kg IP was examined in a behavioral experiment designed toassess behavioral performance on the reversal of a visualdiscrimination. Animals treated with the 3.0 or 30.0 mg/kg of testcompound or with amphetamine needed fewer trials to reach criterionlevels of performance and had better accuracy scores relative to ratstreated with vehicle. Thus, test compound, at certain doses, does seemto enhance behavioral performance in this task similar to that achievedwith d-amphetamine sulfate.

(Methods)

Forty adult male Long-Evans rats (Charles River Laboratories,Wilmington, Mass.) approximately 250 g at the start of training wereused as subjects in this study. Each shipment of rats went throughfive-day isolation prior to introduction to the general population. Ratswere allowed a minimum of one additional week acclimation before operanttraining began.

Test compound was dissolved in sterile 0.9% saline at 3.0, 10.0, and30.0 mg/mL. D-amphetamine, the reference compound, was also dissolved in0.996 sterile saline at 1.0 mg/mL of the amphetamine salt.

After operant training began, rats were housed individually. Access tofood was restricted to 12-20 grams per day to maintain animals at 85-90%free feeding body weight (relative to non-restricted rats). Rats werenever deprived of water and continued gain weight while in the study.

After animals reached the training criteria on Phase 1 of the study,they were designated to one of the treatment groups; groups were matchedfor performance (days to criterion performance) in Phase I. The studywas a mixed design (dose levels x repeated training sessions). The fivedose levels were 1, 3, and 10 mg/kg test compound, 0.9 percent saline(vehicle) and 1.0 mg/kg d-amphetamine sulfate (reference compound) alldelivered intraperitoneal (IP) at 1.0 mL/kg.

Animals were trained in a set of 10 operant testing chambers (MedAssociates) containing two retractable response levers on the frontwall. There were two stimulus lights in the chamber, one situated overeach lever. The food magazine is located between the two response leverson the front wall and food delivery is signaled with a magazine light.Retrieval of the food pellet is detected by a photosensor within thefood magazine. Dim illumination of the chamber is provided by ahouselight over the center of the front wall.

Initially animals were shaped to press a lever for food. During thisphase, both levers were extended into the chamber and the animal wasrewarded with a 45 mg pellet for pressing a lever. The use of a sidebias is prevented by retracting a lever once it exceeds five pressesbeyond the number of presses on the opposite lever. After threeconsecutive days with 100 lever presses subjects were moved to Phase Iof the study. In this phase, animals had to learn to press the leverbeneath the illuminated signal light. On each trial, one of the signallights (randomly chosen) was illuminated for 1.0 sec prior topresentation of the levers (30.0 sec limited hold). After the leversextend into the chamber, a press on the proximal lever resulted in thedelivery of a food pellet. A press on the distal lever resulted in atime out signaled by extinguishing the houselight for 5.0 sec. Aftereither a correct or incorrect press, or an omission, the levers wereretracted for the duration of the variable inter-trial-interval (ITI; 5s+/−2 s). After stable responding (two consecutive days better than 80%correct) was established in this phase, animals began training in thedrug administration portion of the experiment (Phase II).

In Phase II, animals were divided into five groups matched on percentaccuracy and number of trials to criterion. Animals in each group weredosed with one of three doses of rest compound (3.0, 10.0, or 30.0ng/kg, IP), amphetamine (1.0 mg/kg, IP), or with the vehicle (saline)one hour prior to behavioral training. In Phase II the discriminationwas reversed from that of Phase I such that animals were now rewardedfor pressing the lever distal to the cue light. Animals were dosed dailyapproximately 60 min prior to training. Training continued until allanimals achieved two consecutive days above 80% correct on the newdiscrimination.

Data were analyzed using SPSS 12.0 for Windows (SPSS Inc., Chicago,Ill.). A mixed between groups repeated measures ANOVA was conducted onresponse accuracy data. A simple one-way ANOVA was conducted on thetrials to criteria data from Phase II.

(Results)

Response Accuracy. Test compound resulted in significantly betterperformance on the reversal of the visual discrimination as measured bythe percent accuracy. A mixed design ANOVA revealed significant maineffects of session (F_(19,665)=365.60, p<0.001) and group(F_(4,35)=3.08, p=0.028), but more importantly there was a significantgroup by session interaction (F_(76,665)=1.78, p=0.019), Visualinspection of the graph (see FIG. 1) shows that the vehicle and 10.0mg/kg dose of test compound were lower than the 3.0, and 30.0 dose oftest compound and the 1.0 mg/kg dose of d-amphetamine.

Sessions to criteria in Phase II. Test compound resulted insignificantly better performance on the reversal of the visualdiscrimination as measured by the number of session required to reachcriteria (see FIG. 2). A one-way ANOVA revealed an effect of session(F_(4,35)=4.33, p=0.006). Pairwise comparisons (p<0.05) confirm thatmore trials were required for the vehicle group to reach criterionlevels of performance compared to the number of sessions required foranimals that were dosed daily with 3.0, and 30.0 dose of test compoundor the 1.0 mg/kg dose of d-amphetamine (note asterisks in FIG. 2). Thegroup that was given 10.0 mg/kg of test compound did not differ from thevehicle group but was different from the 30 mg/kg dose of test compoundand the d-amphetamine dosed groups. In FIG. 2, “*” denotes p<0.05compared to vehicle control using LSD pairwise comparisons.

Example 2

The test compound administered at 10, 30 and 100 mg/kg subcutaneously(SC) was assessed to determine the influence on spontaneous activity ofwild-type and homozygous mutant dopamine transporter knockout (KO) micethat bear some similarities to patients diagnosed with ADHD. The testcompound selectively reduced activity of the KO mice in a dose-dependentmanner suggesting that the test compound was high efficacious indepressing hyperactivity in dopamine transport KO mice.

(Methods)

Male and female wild-type and homozygous mutant dopamine transporter KOmice (n˜10 mice/genotype/agent) were tested for spontaneous activity inthe open field following a single injection of the vehicle or compound.Mice were placed into the open field for 30 min and administered SC thevehicle (sterile water), 2 mg/kg amphetamine, or three concentrations ofthe test compound (10, 30, 100 mg/kg). All drugs were given in a volumeof 5 mL/kg. Animals were returned to the open field for an additional 90min. Spontaneous activity was evaluated in an automated OmnitechDigiscan apparatus (Accuscan Instruments, Columbus, Ohio). Activity wassummated at 5 min intervals over the 2 h period of testing. Horizontalactivity or locomotion was measured in terms of the total distancecovered in cm, vertical activity or rearing was expressed in terms ofthe total numbers of vertical beam breaks, and stereotypy was quantifiedin terms of repetitive breaks of a given beam or beams with intervals ofless than 1 sec. For the analyses, 10 WT and 10 KO mice were run in eachof the treatment groups with approximately equal numbers of males andfemales assigned to each group. Data were analyzed by the StatisticalPackage for Social Sciences programs (version 11.0 for Windows; SPSSScience, Chicago, Ill.). The results for each dependent variable wereanalyzed by repeated analyses of variance (RMANOVA) for within subjectseffects (group differences over time) and between-subjects effects(tests of main effects and interactions). Bonferroni corrected pair-wisecomparisons were used as the post-hoc tests. A p<0.05 was consideredsignificant.

(Results)

Baseline: KO mice showed higher levels of locomotor, rearing andstereotypical activities compared to WT mice.

Drug Treatment: Amphetamine at 2 mg/kg SC increased locomotor, rearingand stereotypical activities in WT mice and decreased them in KO animalsrelative to the respective vehicle controls. The test compound reducedactivities in a dose-dependent fashion and the 100 mg/kg dose suppressedactivities more efficiently than amphetamine. Please see representativeFIG. 3 for the locomotor activity (distance traveled in cm) collapsedover the 90 min post-injection period for Amphetamine (AMPH) and testcompound. Rearing and stereotyped behavior showed similar results.

Example 3

The test compound was tested for binding to the dopamine, norepinephrineand serotonin transporters and for the effects on dopamine,norepinephrine and serotonin reuptake. The test compound showed weakbinding to the dopamine and norepinephrine transporter and weak effectson dopamine and norepinephrine reuptake compared to cocaine.

(Methods)

Unknowns were weighed and dissolved in DMSO to make a 10 or 100 mM stocksolution, An initial dilution to 50 or 500 μM in assay buffer forbinding, or to 1 or 10 mM in assay buffer for uptake, was made.Subsequent dilutions were made with assay buffer supplemented with DMSO,maintaining a final concentration of 0.1% DMSO. Pipetting was conductedusing a Biomek 2000 robotic workstation.

Concentrations of Test Compound Tested

Assay Concentration Range

Binding:

hDAT 21.6 nM-100 μM

hSERT 21.6 nM-100 μM

hNET 21.6 nM-10 μM

Uptake:

hDAT 31.6 nM-10 μM

hSERT 31.6 nM-100 μM

hNET 31.6 nM-100 μM

Inhibition of Radioligand Binding of [¹²⁵I]RTI-55 to hDAT, hSERT or hNETin Clonal Cells:

Cell preparation: HEK293 cells expressing hDAT, hSERT or hNET insertsare grown to 80% confluence on 150 mm diameter tissue culture dishes andserve as the tissue source. Cell membranes are prepared as follows.Medium is poured off the plate, and the plate is washed with 10 ml ofcalcium- and magnesium-free phosphate-buffered saline. Lysis buffer (10ml; 2 mM HEPES with 1 mM EDTA) is added. After 10 min, cells are scrapedfrom plates, poured into centrifuge tubes, and centrifuged 30,000×g for20 min. The supernatant fluid is removed, and the pellet is resuspendedin 12-32 ml of 0.32 M sucrose using a Polytron at setting 7 for 10 sec.The resuspension volume depends on the density of binding sites within acell line and is chosen to reflect binding of 10% or less of the totalradioactivity.

Assay conditions: Each assay tube contains 50 μl of membrane preparation(about 10-15 μg of protein). 25 μl of unknown, compound used to definenon-specific binding, or buffer (Krebs-HEPES, pH 7.4; 122 mM NaCl, 2.5mM CaCI2, 1.2 mM MgSO₄, 10 μM pargyline, 100 μM tropolone, 0.2% glucoseand 0.02% ascorbic acid, buffered with 25 mM HEPES), 25 id of [ml]RTI-55(40-80 μM final concentration) and additional buffer sufficient to bringup the final volume to 250 μl. Membranes are preincubated with unknownsfor 10 min prior to the addition of the [¹²⁵I]RTI-55. The assay tubesare incubated at 25° C. for 90 min. Binding is terminated by filtrationover GF/Cfilters using a Tomtec 96-well cell harvester. Filters arewashed for six seconds with ice-cold saline. Scintillation fluid isadded to each square and radioactivity remaining on the filter isdetermined using a Wallac μ- or beta-plate reader. Specific binding isdefined as the difference in binding observed in the presence andabsence of 5 μM mazindol (HEK-hDAT and HEK-hNET) or 5 μM imipramine(HEK-hSERT). Two or three independent competition experiments areconducted with duplicate determinations. GraphPAD Prism is used toanalyze the ensuing data, with IC₅₀ values converted to K_(i) valuesusing the Cheng-Prusoff equation(K_(i)=IC₅₀/(1+([RTI-55]/K_(d)RTI-55))).

Filtration Assay for Inhibition of [³H]Neurotransmitter Uptake in HEK293Cells Expressing Recombinant Biogenic Amine Transporters:

Cell preparation: Cells are grown to confluence as described above. Themedium is removed, and cells are washed twice with phosphate bufferedsaline (PBS) at room temperature. Following the addition of 3 mlKrebs-HEPES buffer, the plates are warmed in a 25° C. water bath for 5min. The cells are gently scraped and then triturated with a pipette.Cells from multiple plates are combined. One plate provides enough cellsfor 48 wells, which is required to generate data on two complete curvesfor the unknowns.

Uptake inhibition assay conditions: The assay is conducted in 96 1-mlvials. Krebs-HEPES (350 μl) and unknowns, compounds used to definenon-specific uptake, or buffer (50 μl) are added to vials and placed ina 25° C. water bath. Specific uptake is defined as the difference inuptake observed in the presence and absence of 5 μM mazindol (HEK-hDATand HEK-hNET) or 5 μM imipramine (HEK-hSERT), Cells (50 μl) are addedand preincubated with the unknowns for 10 min. The assay is initiated bythe addition of [³H]dopamine, [³H]serotonin, or [³H]norepinephrine (50μl, 20 nM final concentration). Filtration through Whatman GF/Cfilterspresoaked in 0.05% polyethylenimine is used to terminate uptake after 10min. The IC₅₀s are calculated applying the GraphPAD Prism program totriplicate curves made up of 6 drug concentrations each. Two or threeindependent determinations of each curve are made.

(Results)

The test compound was tested for its effects on radioligand([¹²⁵I]RTI-55) binding to and [³H]dopamine uptake by HEK cellsexpressing eDNA for the human dopamine transporter (HEK-hDAT cells), itseffects on radioligand ([¹²⁵I]RTI-55) binding and [³H]serotonin uptakeby HEK cells expressing eDNA for the human serotonin transporter(HEK-hSERT cells), and its effects on radioligand ([¹²⁵I]RTI-55) bindingand [³H]norepinephrine uptake by HEK cells expressing eDNA for the humannorepinephrine transporter (HEK-hNET cells).

In HEK-hDAT cells, the affinity of the compound for the binding site waslower than the affinity of cocaine, the standard compound, for the samesite(s). The K_(i) value for the displacement of [¹²⁵I]RTI-55 by thetest compound was 14,200 nM, and the K_(i) value for cocainedisplacement of [¹²⁵I]RTI-55 binding was 236 nM. In the uptake assaystest compound was less potent at blocking the uptake of [³H]dopamine,with an IC₅₀ value of 2900 nM, as compared to the potency of cocaine.(IC₅₀=385 nM). A Hill coefficient other than one suggests complexinteractions with binding or uptake sites (Table 1).

In HEK-hSERT cells, the affinity of the compound for the binding sitewas lower than the affinity of cocaine, the standard compound, for thesame site(s). The K_(i) value for the displacement of [¹²⁵I]RTI-55 bytest compound was 81,500 nM, and the K_(i) value for cocainedisplacement of [ml]RTI-55 binding was 361 nM. In the uptake assays31,827 was less potent at blocking the uptake of [3H]serotonin, with anIC₅₀ value greater than 100 μM, as compared to the potency of cocaine(IC50=355 nM) (Table 2).

In HEK-hNBT cells, the affinity of the compound for the binding site waslower than the affinity of cocaine, the standard compound, for the samesite(s). The K_(i) value for the displacement of [¹²⁵I]RTI-55 testcompound was 3700 nM, and the K_(i) value for cocaine displacement of[¹²⁵I]RTI-55 binding was 505 nM. In the uptake assays test compound wasless potent at blocking the uptake of [³H]norepinephrine, with an IC₅₀value of 4400 nM, as compared to the potency of cocaine (IC₅₀=194 nM)(Table 3).

TABLE 1 HEK-hDAT cells Test Compound Cocaine [¹²⁵I]RTI-55 Binding K_(i)(nM) 14,200 ± 3,500 236 ± 58 Hill coefficient −0.77 ± 0.12 −0.83 ± 0.04[³H]Dopamine Uptake IC₅₀ (nM) 2900 ± 920 385 ± 54

TABLE 2 Effects of test compound on HEK-hSERT HEK-hSERT cells TestCompound Cocaine [¹²⁵I]RTI-55 Binding K_(i) (nM) 81,500 ± 2,900 361 ± 65Hill coefficient −2.28 ± 0.05 −0.77 ± 0.04 [³H]Serotonin Uptake IC₅₀(nM) >100 μM 355 ± 39

TABLE 3 Effects of test compound on HEK-hNET cells HEK-hNET cells TestCompound Cocaine [¹²⁵I]RTI-55 Binding K_(i) (nM) 3700 ± 1000 505 ± 67Hill coefficient −1.45 ± 0.34  −0.67 ± 0.07 [³H]NE Uptake IC₅₀ (nM) 4400± 1100 194 ± 29

Numbers represent the means SEM from at least three independentexperiments, each conducted with duplicate (for binding assays) ortriplicate (for uptake assays) determinations. When the K_(i) or theIC₅₀ for the test compound is greater than 10 μM, only two experimentsare conducted and no standard error is reported.

Example 4

The test compound was tested for effects on extracellular mionoaminergicneurotransmitter levels, sampled via in vivo brain microdialysis inprefrontal cortical and striatal brain areas of freely-moving, consciousrats. Administration of the test compound at 30 mg/kg resulted inincreased striatal dopamine and prefrontal norepinephrine.

(Methods)

Brain dialysates were collected from male Sprague-Dawley rats, which hadbeen chronically implanted with cortical and striatal microdialysisguide cannulae and probes. The effects of different doses of testcompound (10 and 30 mg/kg, administered subcutaneously) or vehicle(saline, 0.9% NaCl) were evaluated in three 50 minute baseline samplesand eight consecutive 50 minute post-administration samples. The levelsof dopamine, norepinephrine and serotonin for the two different brainareas were analyzed using HPLC/ECD analysis to determine any effects ofthe compound.

(Results)

Test compound at a dose of 10 mg/kg had no consistent effect onextracellular neurotransmitter levels in either brain region tested. Ata dose of 30 mg/kg only, test compound caused increases in striataldopamine and prefrontal cortical norepinephrine of rather variablemagnitude, without having any significant effect on the othertransmitters investigated.

FIG. 4 shows effects of administration of Test Compound (10 and 30 mg/kgs.c.) or vehicle (0.9% NaCl) on extracellular dopamine concentrations inthe striatum of rats during 3 baseline samples and 8 consecutivepost-administration samples, and FIG. 5 shows effects of administrationof Test Compound (10 and 30 mg/kg s.c.) or vehicle (0.9% NaCl) onextracellular norepinephrine concentrations in the prefrontal cortex ofrats during 3 baseline samples and 8 consecutive post-administrationsamples.

In FIGS. 4 and 5, results are expressed as the average percentage changecompared to the individual's average baseline value. The arrow indicatesthe time of administration of test compound. The average value (andcorresponding S.E.M.) are shown for each 50 minute sample period of n=12rats for each group (NB: individual data points may be based on fewersamples owing to incidental loss of dialysate samples).

REFERENCES CITED

All references cited herein are incorporated herein by reference intheir entirety and for all purposes to the same extent as if eachindividual publication or patent or patent application was specificallyand individually indicated to be incorporated by reference in itsentirety for all purposes.

The discussion of references herein is intended merely to summarize theassertions made by their authors and no admission is made that anyreference constitutes prior art. Applicants reserve the right tochallenge the accuracy and pertinence of the cited references.

The present invention is not to be limited in terms of the particularembodiments described in this application, which are intended as singleillustrations of individual aspects of the invention. Many modificationsand variations of this invention can be made without departing from itsspirit and scope, as will be apparent to those skilled in the art.Functionally equivalent methods and apparatus within the scope of theinvention, in addition to those enumerated herein will be apparent tothose skilled in the art from the foregoing description and accompanyingdrawings. Such modifications and variations are intended to fall withinthe scope of the appended claims. The present invention is to be limitedonly by the terms of the appended claims, along with the full scope ofequivalents to which such claims are entitled.

1. A method of treating attention deficit hyperactivity disorder (ADHD),comprising administering a therapeutically effective amount of acompound having structural Formula (1) or a pharmaceutically acceptablesalt thereof, to a mammal in need of treatment:

wherein R is selected from the group consisting of hydrogen, lower alkylof 1 to 8 carbon atoms, halogen selected from F, Cl, Br and I, alkoxycontaining 1 to 3 carbon atoms, nitro, hydroxy, trifluoromethyl, andthioalkoxy containing 1 to 3 carbon atoms; x is an integer of 1 to 3,with the proviso that R may be the same or different when x is 2 or 3;and R₁ and R₂ can be the same or different from each other and areindependently selected from the group consisting of hydrogen, loweralkyl of 1 to 8 carbon atoms, aryl, arylalkyl, and cycloalkyl of 3 to 7carbon atoms; or R₁ and R₂ can be joined to form a 5 to 7-memberedheterocycle substituted with a member selected from the group consistingof hydrogen, alkyl, and aryl groups, wherein the heterocyclic compoundcan comprise 1 to 2 nitrogen atoms and 0 to 1 oxygen atom, wherein thenitrogen atoms are not directly connected with each other or with theoxygen atom.
 2. The method of claim 1, wherein R is hydrogen and x=1. 3.The method of claim 1, wherein R, R₁ and R₂ are hydrogen and x=1.
 4. Themethod of claim 1, wherein the compound having structural Formula (1) isan enantiomer substantially free of other enantiomers or an enantiomericmixture wherein one enantiomer of the compound having structural Formula(1) predominates.
 5. The method of claim 4, wherein one enantiomerpredominates to the extent of about 90% or greater.
 6. The method ofclaim 5, wherein one enantiomer predominates to the extent of about 98%or greater.
 7. The method of claim 4, wherein the enantiomer is (S) or(L) enantiomer as represented by Structural Formula (1a):


8. The method of claim 7, wherein one enantiomer predominates to theextent of about 90% or greater.
 9. The method of claim 8, wherein oneenantiomer predominates to the extent of about 98% or greater.
 10. Themethod of claim 7, wherein R, R₁ and R₂ are hydrogen and x=1.
 11. Themethod of claim 4, wherein the enantiomer is (R) or (D) enantiomer, asrepresented by Structural Formula (1 b):


12. The method of claim 11, wherein one enantiomer predominates to theextent of about 90% or greater.
 13. The method of claim 12, wherein oneenantiomer predominates to the extent of about 98% or greater.
 14. Themethod of claim 11, wherein the enantiomer is(R)-(beta-amino-benzenepropyl) carbamate.
 15. The method of claim 14,wherein the enantiomer of (R)-(beta-amino-benzenepropyl) carbamatepredominates to the extent of about 90% or greater.
 16. The method ofclaim 15, wherein the enantiomer of (R)-(beta-amino-benzenepropyl)carbamate predominates to the extent of about 98% or greater.
 17. Apharmaceutical composition for treating ADHD, comprising a compoundhaving structural Formula (1) or a pharmaceutically acceptable saltthereof:

wherein R is selected from the group consisting of hydrogen, lower alkylof 1 to 8 carbon atoms, halogen selected from F, Cl, Br and I, alkoxycontaining 1 to 3 carbon atoms, nitro group, hydroxy, trifluoromethyl,and thioalkoxy containing 1 to 3 carbon atoms; x is an integer of 1 to3, with the proviso that R may be the same or different when x is 2 or3; and R₁ and R₂ can be the same or different from each other and areindependently selected from the group consisting of hydrogen, loweralkyl of 1 to 8 carbon atoms, aryl, arylalkyl, and cycloalkyl of 3 to 7carbon atoms; or R₁ and R₂ can be joined to form a 5 to 7-memberedheterocycle substituted with a member selected from the group consistingof hydrogen, alkyl, and aryl groups, wherein the heterocyclic compoundcan comprise 1 to 2 nitrogen atoms and 0 to 1 oxygen atom, wherein thenitrogen atoms are not directly connected with each other or with theoxygen atom.